In a cardiac catheter test, a contrast agent is introduced to a patient using an injector head, and the test is done while imaging the affected part. For example, utilizing a coronary angiography of providing images of cardiac blood vessels, an operation of blood vessel is performed for widening a narrowed lesion by catheter method. Utilizing left ventricular angiogram imaging the left ventricle of the heart, behavior of cardiac muscle around the left ventricle is tested, by monitoring systole and diastole states of the heart.
Examples of such an injector head are disclosed, for example, in Japanese Patent Laying-Open Nos. 10-165396 (PTD 1) and 10-244002 (PTD 2).